Training Zones Calculator

What makes this calculator different? Most calculators give you pace zones or heart rate zones. This one gives you both, plus your VDOT score, estimated VO2max, and a visual breakdown of the 80/20 rule so you know exactly how much easy running you should be doing.

How the Training Zones Calculator Works

Step 1: Enter Your Recent Race Result

Start with a race you ran recently, anything from a 5K to a marathon. The more recent, the more accurate. Your race result is the gold standard for calculating your current fitness level. We use an algorithm based on Jack Daniels’ running formula, one of the most proven methods in sports science, to convert your race time into a VDOT score (Velocity at VO2max).

Step 2: Add Heart Rate Info (Optional)

If you want heart rate zones, add your age and resting heart rate. Don’t know your resting HR? Measure it tomorrow morning before getting out of bed, average it over 3-5 days for the best result. We use the Karvonen formula, which is more accurate than simple percentage-of-max calculations because it accounts for your actual fitness level.

Step 3: Choose Your Display Preference

Prefer minutes per mile or minutes per kilometer? Pick your poison. We’ll show all your zones in your preferred unit.

Step 4: Get Your Zones

Hit calculate and boom, you’ve got personalized training zones, your VDOT score, estimated VO2max, heart rate zones, and a weekly training split based on the scientifically-backed 80/20 rule.

Understanding Your Pace Zones

Easy/Long Run Pace (Zone 1)

The foundation of every training plan. This is your conversational pace, if you can’t speak in full sentences, you’re going too fast. Easy runs should make up about 80% of your running. They build aerobic capacity, improve efficiency, and let your body recover from harder efforts. Counterintuitively, running slower actually makes you faster.

Marathon Pace (Zone 2)

Your goal marathon pace. If you’re training for a 26.2-miler, this is the pace you’ll target during long runs and marathon-specific workouts. It’s faster than easy but still sustainable for extended periods. Even if you’re not training for a marathon, this zone is great for steady-state workouts that build lactate threshold.

Threshold/Tempo Pace (Zone 3)

The “comfortably hard” zone. Threshold runs teach your body to clear lactate more efficiently and boost your aerobic ceiling. Typically done for 20-40 minutes in a single session or split into repeats. This is where you feel strong but challenged, not sprinting, but definitely working.

VO2max/Interval Pace (Zone 4)

Short, fast, powerful work. These are your 3-5 minute repeats: hard enough that conversation stops, but not so hard you’re gasping. VO2max work maximizes your aerobic power and teaches your body to sustain high speeds. Typically 4-8 repeats per session with recovery between.

Speed/Repetition Pace (Zone 5)

All-out effort for short bursts. These are your 200m, 400m, and 800m repeats, the work that builds leg speed and power. Done less frequently (1x per week, max), speed work keeps you sharp and quick. Usually reserved for runners training for shorter races (5K and below).

Understanding Your Heart Rate Zones

Heart rate training gives you a biometric way to measure effort. Unlike pace (which can vary based on terrain, weather, and fatigue), your heart rate is honest, it tells you exactly how hard you’re working.

Zone 1 (Recovery): 50–60% of heart rate reserve
Light activity, easy running, active recovery days. Your heart rate is low and your breathing is easy.

Zone 2 (Aerobic/Easy): 60–70% of heart rate reserve
This is your sweet spot for most running. Builds aerobic base, burns fat efficiently, and feels sustainable.

Zone 3 (Tempo/Threshold): 70–80% of heart rate reserve
You’re working but not maxing out. Great for steady-state runs and tempo workouts. Conversation is possible but not comfortable.

Zone 4 (VO2max/Interval): 80–90% of heart rate reserve
Now we’re talking hard work. Your breathing is rapid and controlled. This zone builds aerobic power and speed.

Zone 5 (Max Effort): 90–100% of heart rate reserve
All-out effort. Sustainable only for short periods (minutes, not hours). Used for sprint work and maximal efforts.

What Is VDOT?

Your VDOT score (named after running legend Jack Daniels) represents your current running fitness level. Think of it as a single number that summarizes your aerobic capability. The higher your VDOT, the better your current fitness.

What’s a good VDOT?

• Below 40: Beginning/recreational runners
• 40–50: Competitive amateur runners
• 50–60: Strong competitive runners
• 60+: Elite/professional runners

Your VDOT changes based on your fitness level. When you train consistently and race faster, your VDOT goes up. When you take time off or reduce training, it goes down. It’s a living metric that reflects your current state.

The 80/20 Training Rule Explained

This is where science meets common sense. Research by Renato Canova and others shows that elite runners spend about 80% of their training time at easy, conversational paces and only 20% at harder intensities. Yet most amateur runners do the opposite, constant moderate-intensity running that’s too hard to be truly easy and too easy to drive adaptation.

Why 80/20 works:

• Easy runs (80%) build aerobic capacity, improve fat burning, and promote recovery
• Hard runs (20%) drive fitness gains and teach your body to sustain faster paces
• The contrast between easy and hard is what creates adaptation
• It prevents overtraining and reduces injury risk
• Your body actually recovers better when easy days are actually easy

Most runners can fit their hard work into 1–2 focused sessions per week: maybe one tempo run and one interval/speed session, with the rest of the week being genuine easy running.

How Accurate Are These Zones?

This calculator uses proven sports science formulas:

• VDOT calculation: Jack Daniels’ running formula, based on decades of research
• Heart rate zones: Karvonen formula, which accounts for your fitness level
• Training zones: Evidence-based paces used by elite coaches worldwide

That said: These zones are estimates. Use them as guides, not gospel. If a pace feels drastically different from what your body tells you, trust your body. Factors like weather, fatigue, altitude, and how you slept all affect how a given pace feels on any given day.

The calculator is most accurate when:

• Your race result is recent (within 3 months)
• The race was an honest effort (you weren’t sandbagging or running injured)
• You’re measuring resting HR correctly (morning, before getting up)

Tips for Training by Zones

Make Easy Days Actually Easy

This is the hardest thing to do, and it’s also the most important. Your easy pace might feel slower than you expect. That’s correct. Easy should feel genuinely easy, boring, even. You should be able to hold a full conversation without any breathing difficulty. If you can’t, you’re too fast.

Structure Your Week

A common structure for 5-6 days of running:

• 3–4 easy runs (conversational pace)
• 1 tempo or threshold run (comfortably hard)
• 1 VO2max or interval session (hard repeats)
• 1 long run (easy pace, longer duration)
• 1–2 rest or cross-training days

Don’t Ignore Recovery

The magic of training zones is the contrast. Hard work creates stimulus, but easy running (and rest) create adaptation. Skip the easy running and recovery, and you’ll stagnate or burn out. This is why 80/20 is so powerful.

Adjust for Conditions

Bad weather? Tough terrain? Running on tired legs? Slow down. Your pace zones assume normal conditions. If conditions are harder, your effort level goes up, so your pace should come down to stay in zone.

Track Perceived Effort Too

Heart rate zones and pace zones are tools, not rules. Always factor in perceived effort. If you feel way harder than a pace or HR zone suggests, you’re probably fatigued and should ease off. If you feel fresh and strong, you can push a bit harder.

FAQs About Training Zones

Q: Do I need a running watch to use training zones?
A: Not at all. You can use a running watch with GPS (Garmin, Apple, Coros, etc.), a fitness tracker, or even an old-school stopwatch. You just need to know your pace. For heart rate zones, you’ll want a heart rate monitor (built into most modern watches).

Q: What if I don’t know my resting heart rate?
A: No problem! The calculator works without it, just skip the HR zones and use pace zones. If you want HR zones, spend a few mornings measuring it before you get out of bed, average it, and come back.

Q: Should I follow these zones exactly, or is there flexibility?
A: Use them as guides. Your body isn’t a computer. Some days you’ll run slightly faster or slower than the zone suggests, and that’s okay. The zones keep you in the ballpark; perceived effort and context matter too.

Q: How often should I recalculate my zones?
A: Every time you race! Your zones are only as accurate as your most recent effort. If you race again in 2 months, recalculate. If you haven’t raced in 6 months, you can estimate based on a recent tempo run or do a time trial to get a fresh data point.

Q: What if my recent race was a terrible day? Does that mess up my zones?
A: If you bombed due to illness, injury, or going out too hard and bonking, that race doesn’t represent your fitness. Use an older, better-executed race result instead. The calculator is only as good as the effort you put in.

Q: Can I use a marathon result to calculate 5K pace zones?
A: Absolutely. The formula works across distances. A well-run marathon gives you solid data for pace zones, even if you’re not training for another marathon.

Q: Do I need all five pace zones?
A: Not necessarily. Most runners need:

• Easy pace (your bread and butter)
• Tempo pace (for a weekly hard workout)
• VO2max pace (for fast intervals)

The marathon and speed zones are bonuses based on your training goals.

The Science Behind the Numbers

This calculator uses Jack Daniels’ VDOT formula, one of the most respected systems in running. Here’s the thinking:

1. Your race result reveals your current aerobic capacity
2. VDOT quantifies that capacity as a single number
3. Training zones are percentages of VDOT that correspond to different physiological adaptations
4. Heart rate zones use the Karvonen formula, which is more accurate than simple percentage-of-max because it accounts for your individual resting HR and fitness level

The result: personalized zones that reflect your unique physiology, not generic one-size-fits-all zones.

Common Training Mistakes This Calculator Helps You Avoid

Mistake 1: Running everything in the gray zone
Most of your running should be easy, and some should be hard. Constant moderate-intensity running is neither and wastes energy. This calculator shows you the difference.

Mistake 2: Running easy days too fast
You’re fit, so easy feels slow. But slow easy runs are what build your aerobic base and let you recover from hard work. The calculator makes this crystal clear with specific pace ranges.

Mistake 3: Running hard days not hard enough
When you do tempo or interval work, you should be truly working. This calculator shows you the paces that actually challenge your aerobic system.

Mistake 4: Ignoring heart rate as a tool
Pace zones are great, but heart rate gives you real-time feedback about how hard you’re actually working. Use both.

Mistake 5: Never reassessing
Your fitness changes. A zones calculator from 6 months ago might not reflect who you are now. Recalculate when you race.

Why I Ditched Perceived Effort and Started Using Training Zones (Coach’s Perspective)

I’ll be honest: I resisted training zones for years. I thought they were overcomplicating something simple. But after I started actually using them with runners, I realized I’d been leaving free speed on the table. Most runners are much more capable than they think, but they’re training inefficiently because they’re either too slow on easy days or too slow on hard days.

Training zones aren’t limiting they’re liberating. They give you permission to run slow on easy days (which actually makes you faster long-term) and a clear target for hard days (which ensures you’re getting the stimulus you need).

Understanding VO2max: What It Means and Why It Matters

VO2max is the maximum amount of oxygen your body can utilize during intense exercise, measured in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). A higher VO2max means a higher aerobic capacity and, generally, better running fitness.

Elite male marathoners often have VO2max values in the 70–85 ml/kg/min range. Recreational runners typically see values between 40–60. The good news? VO2max is trainable. Zone 4 (VO2max) workouts specifically target this system, and consistent training can improve your VO2max by 15–25% over a season.

Resting Heart Rate: How to Measure It and What It Means

Your resting heart rate is one of the most telling metrics of running fitness. A lower resting HR generally indicates better cardiovascular fitness and aerobic capacity. Elite distance runners often have resting HRs in the 40–50 BPM range, while fit recreational runners might be in the 50–60 BPM range.

To measure resting HR correctly, take it first thing in the morning before you get out of bed. Measure for 60 seconds (or 15 seconds and multiply by 4). Average three mornings for your baseline. Track it over time as your fitness improves, it should slowly decrease.